A DESCRIPTION OF THE PROBLEM :
Asserts equivalence to the regex "(?:(?<=\w)(?=\W)|(?<=\W)(?=\w))", but this does not match boundaries with the start or the end of the line.
"\bhello\b" does match "hello", so perhaps the regex "(?:(?<=\w)(?!\w)|(?<!\w)(?=\w))" would be more accurate?


FREQUENCY : always